包覆重钙粉为填充剂的橡胶加工及性能

Processing and Properties of Rubber Modified by Coated Heavy Calcium Powder as the Filler

重钙粉作为填充剂被广泛应用于橡胶加工过程,但由于其表面具有极性,分散性较差,导致与橡胶材料界面结合较差,影响了橡胶产品的抗拉强度、断裂伸长率等力学性能。本文采用沉淀法,在CaCl2-H2O-NH3-CO2体系中生成碳酸钙直接结晶于重钙粉颗粒表面,实现对重钙粉的表面包覆,将n(CaCl2)∶n(重钙粉)=1∶100、5∶100、10∶100的包覆重钙粉填充到天然橡胶和再生胶中,橡胶的力学性能与填充未包覆重钙粉的橡胶相比有了一定的提升。通过比较,在填充量较大(8.5%、15%)时,包覆重钙粉橡胶产品在硬度、定伸应力等力学性能上要好于轻钙粉橡胶产品;在填充量(5%、8.5%)时,包覆重钙粉橡胶产品的抗拉强度、断裂伸长率接近于白炭黑,硬度高于白炭黑橡胶产品。

Heavy calcium powder is widely used as a filler in rubber processing, but the interface with the rubber material is poorly combined due to high polarity and poor dispersibility of powders, which affects the mechanical properties such as tensile strength and elongation at break of the rubber product. In this paper, the precipitation method is used to form calcium carbonate which is directly crystallized on the surface of heavy calcium powder particles in CaCl2-H2O-NH3-CO2 system. If n (CaCl2)∶ n (heavy calcium powder)=1∶ 100, 5∶ 100 , 10∶ 100 coated calcium powder are filled into natural rubber and recycled rubber, the mechanical properties of rubber are some what improved compared to rubber filled with uncoated calcium powder. The filling amount is 8.5% and 15%, in the mechanical properties such as hardness and modulus, the coated calcium powder rubber product is obviously superior to the light calcium powder rubber product;when it comes to 5% or 8.5%, the tensile strength and elongation at break of the coated heavy calcium rubber product are close to that of silica, and the hardness is higher than rubber products filled with silica.